Method for ignition on combustion engines



Feb. 4, 1930. J. BETHENOD 1,745,830

METHOD FOR IGNITION ON COMBUSTION ENGINES Filed March 28, 1928 itwy Patented Feb. 4, 1930 UNITED STATES JOSEPH IBE'I'HENOD, OF PARIS, FRANCE METHOD FOR IGNITION ON COMBUSTION ENGINES Application filed March 28, 1928, Serial No. 265,448, and in Trance April 1, 1927.

This invention relates to a new method for ignition on combustion engines. The method consists, substantially, in supplying the ignition plug with the discharge of a condenser permanently associated with the said plug, the said condenser being charged to-a voltage not suflicient for striking the spark; the striking of the spark is secured at'the proper time by an auxiliary high tension discharge which produces through the space between the plug electrodes a spark, called the pilot spark, which is sufficient to produce'the ionization of the spark gap. This said auxiliary spark is itself obtained by means of a magneto, or by an induction coil with a,distributer mechanically driven by the engine, or by any other equivalent means. The necessary power for producing the ilot spark being in fact comparatively sma 1, it is easy to understand that the device which has been described, allows the maintenance of an extremely powerful ignition, without requiring the interrupting device, which controls the times of ignition, to handle a large amount of energy.

The invention will be well understood by reference to the accompanying drawings, which give as examples, some forms 'of construction:

Figure 1 shows diagrammatically one circuit arrangement for an ignition system embodying my invention and Fig. 2 illustrates a modified circuit arrangement of an ignition system embodying my-invention.

Referring to Fig. 1, 1 is a condenser permanently associated with the ignition plug. The ignition plug is shown diagrammatically at 2. 3 is the common ground for all of the installation. Condenser 1 is charged by the source 4. The source 4-. is for example, a direct-current dynamo with .a comparatively high voltage. A convenient impedance 5 is inserted, if desired, in the load circuit so as to limit more particularly the source output when condenser 1 is discharging through the plug 2. In order to produce that discharge at the proper time, an, auxiliary spark gap is placed in series with a high voltage condenser 7, and the terminals of this assembly are connected to the plug terminals. Condenser 7 is sup- 50 plied, for example, bythe secondary'circuit of a high-tension magneto 8 of a usual type, synchronously driven, as is usual, by the combustion engine. At the time of breaking of the primary circuit of magneto 8, the condenser 7 is suddenly charged, and it immedi- 65 ately discharges through the sparkgap 6.

A portion of the discharge flows through the space between the electrodes of the plug 2, and thenproduces, according to my invention, the discharge of condenser 1. In order to avoid the possibility that the other portion of the initial discharge of condenser 7, which flows through condenser 1, may become too great, I insert if desired, at 12 a reactance coil of suitable reactance. It is to be observed that in case the voltage of the source 4 is, for example, several hundred volts, the capacity 1 will be much larger than the capacity '7 if desired, the capacity 1 will be an electrolytic condenser, or a colloidal one. Of 7 course, magneto 8 can be replaced by an induction coil with a mechanically driven dis-- tributer 'the primary of the coil being supplied by a storage battery or the like. 0

Referring to Fig. 2, the condenser 7 is also charged by means of a high-tension magneto or the like,-.but in this case that condenser is a part with thespark gap 6. of an oscillating circuit including a coil 9. This latter is coupled through its mutual inductance with a coil 10, which is inserted between condenser 1 and plug 2. Furthermore it is desirable that the condenser 11, having a much smaller capacity than the condenser 1, be connected to the terminals of the plug.

' Of course the scheme of Figure 2 can have many other forms of realization. Especially if desired the combination 7, 6, 9, can be re placed by a high-tension source of any other 4 type; for example, it is possible to use a triode tube generator of the type well known in radio. The spark control for the plug can then be made by means of a single rotating switch, synchronously driven by the combustion engine, and preferably operating upon the grid circuit of the triode tube. This switch is then called upon to handle a very small amount of ener the intensity of the current which flows t rough it being practically zero.

. the plug, and means including an independof course, all these modes of realization can be easily used in the case of engines having more than one cylinder, by means of adding a high-tension distributer, or the like.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In an ignition system for combustion engines, in combination, a plug, a condenser permanently associated with said plug, a power supply having a high internal impedance for charging said condenser at a voltage lower than the disrupting voltage of ent source of current for starting the discharge between the electrodes of the said plug.

' 2. In. an ignition system for combustion engines, in combination a plug, a condenser permanently associated with said plug, a power supply having a high internal impedance for charging said condenser at a voltage lower than the disrupting voltage of the plug, and an auxiliary oscillating circuit supplied at high voltage from an independent current source for starting the discharge between the electrodes of the said plug.

3. In an ignition system for combustion engines, in combination a plug, a condenser permanently associated with said plug, a power supply having a high internal impedance for charging said condenser at a voltage lower than the disrupting Voltage of the plug, and an auxiliary oscillating cir-' cuit supplied at high voltage from an independent current source and electrically connected to the plug circuit.

4. In an ignition system for combustion engines, in combination a plug, a condenser permanently associated with said plug, a power supply having a high internal impedance for charging said condenserat a voltage lower than the disrupting voltage of the plug, a primary auxiliary oscillating circuit supplied at high voltage from an independent source and indirectly coupled with the plug circuit, and a secondary oscillating circuit electrically connected to the plug circuit and including the said condenser charged from the main power supply, and another condenser shunting the plug and having a capacity which is very much smaller than the capacity of the said condenser charged from the main power supply.

JOSEPH BETHENOD. 

